WO2020202646A1 - Sliding nozzle plate production method - Google Patents

Abstract

The objective of the invention is to provide a production method and a plate for a sliding nozzle plate comprising a refractory wherein the occurrence of cracks has been suppressed even when high temperature heat treatment is performed.　This sliding nozzle plate production method is characterized by comprising: mixing (S1 and S2), when 100% by mass is the total, 2 to 23% by mass of Al₄SiC₄, and 2 to 10% by mass of a carbon material, the remainder being a phenol resin with a moisture content of 1% or lower and one or more from among alumina, alumina-zirconia, zirconia mullite, magnesia, and magnesia-spinel; and thereafter, heat treating (S4 and S5) at a heating temperature of 150 to 1,400°C. The plate of the present invention is characterized by being produced by this production method.

Description

Manufacturing method of plate for sliding nozzle

The present invention relates to a method for manufacturing a plate for a sliding nozzle.

The molten steel is discharged from the container for storing the molten steel via the nozzle provided in the container. The nozzle includes a sliding nozzle used to control the flow rate of the molten steel to be discharged. The sliding nozzle has two sliding nozzle plates, an upper plate and a lower plate having an inner hole, or three sliding nozzle plates to which an inner plate is added, and these sliding nozzle plates are relatively slidable. As a result, the flow rate of the molten steel is controlled by adjusting the opening degree of the inner hole which is the molten steel flow path.

The sliding nozzle plate is made of refractory material. Refractories include calcined carbon-containing plate refractories in which a raw material mainly composed of alumina is used as an aggregate, various metals, carbides, nitrides, carbon materials, etc. are added and fired at a temperature exceeding 1000 ° C. Non-firing carbon-containing plate refractories heat-treated below are widely known. As the raw material for the aggregate of refractories, alumina, mullite, zirconia mullite, alumina zirconia, spinel, magnesia and the like are used in combination according to the desired characteristics.

In this refractory, the structure is densified by adjusting the particle size composition, etc., to suppress the reaction between oxygen and outside air contained in the molten steel and carbon in the structure. However, densification of the structure leads to an increase in the amount of thermal expansion of the entire refractory. As a result, the thermal shock resistance of the refractory may decrease.

In addition, by incorporating a carbon material that is difficult to oxidize into the refractory and by adding an antioxidant such as oxides, carbides, nitrides, and metals, the decarburization reaction that leads to melting damage of the refractory can be suppressed. Has been done. However, under the above-mentioned usage conditions, tissue embrittlement is likely to occur on the working surface in contact with the molten steel due to the loosening of the structure due to repeated heat reception (heat history) and the oxidation reaction of the carbon material. Then, the components contained in the molten steel may infiltrate into the structure from the operating surface, leading to melting damage of the refractory.

Further, as an antioxidant, metal powders such as Al and Al—Mg are widely known. If the particle size of these metal powders is fine, there is a risk of explosion during production, so it is difficult to use powders having a particle size smaller than a predetermined value. In addition, metal powders such as Al and Al—Mg change to Al ₄ C ₃ in a temperature range of 1000 ° C. or higher, which causes a problem that the corrosion resistance of refractories is lowered. Also known is a carbide, such as B _{4 C} and SiC as an antioxidant. The effect of adding these carbides was not sufficiently exhibited at a high temperature of 1500 ° C. or higher, and it was difficult to continue densification of the refractory.
To solve such a problem, as shown in Patent Document 1, it has been studied to contain Al ₄ SiC ₄ in a refractory material. Al ₄ SiC ₄ contributes to the densification of the structure of refractories.

Japanese Patent Application Laid-Open No. 8-119719

However, the refractory material containing Al ₄ SiC ₄ has a problem that cracks are likely to occur. Specifically, a refractory material that has been heat-treated at a particularly high temperature (for example, 1200 ° C. or higher) is prone to cracking.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a plate for a sliding nozzle made of a refractory material in which the occurrence of cracks is suppressed even if heat treatment is performed at a high temperature.

The method for manufacturing a plate for a sliding nozzle of the present invention (hereinafter, referred to as the manufacturing method of the present invention) for solving the above problems is 2 to 23 mass% of Al ₄ SiC ₄ and 2 to 2 to 23 mass% when the whole is 100 mass%. After mixing 10 mass% of carbon material, one or more of alumina, alumina-zirconia, zirconia mullite, magnesia, magnesia-spinel with the balance, and phenol resin having a water content of 1% or less, the temperature is 150 to 1400 ° C. It is characterized by heat treatment at the heating temperature of.

The plate produced by the production method of the present invention uses a phenol resin having a water content of 1% or less. According to this configuration, even if heat treatment is performed at a high temperature, the effect of forming a plate for a sliding nozzle made of a refractory material in which the generation of cracks is suppressed is exhibited.

It is a flowchart which shows each process of the manufacturing method of an embodiment.

Hereinafter, the present invention will be specifically described with reference to embodiments.
[Production method]
In the manufacturing method of this embodiment, a plate for a sliding nozzle is manufactured in each step shown in FIG.
First, the raw material for the sliding nozzle plate is prepared (raw material preparation step: S1). Specifically, Al ₄ SiC ₄ , carbon material, alumina, alumina-zirconia, zirconia mullite, magnesia, magnesia-spinel, and a phenol resin having a water content of 1% or less are prepared. Each of these raw materials is prepared in powder form.

Al ₄ SiC ₄ contributes to the densification of the structure of the manufactured plate. Al ₄ SiC ₄ generates a gas containing Al by the reaction when exposed to a high temperature in the presence of carbon. The gas containing Al diffuses throughout the voids in the plate (refractory). Then, it reacts with CO gas and recondenses as Al ₂ O ₃ and carbon. This recondensation (particularly the recondensation of Al ₂ O ₃ ) ultimately contributes to the densification of the structure. That is, the reaction of the following formula (1) proceeds.
Al ₄ SiC ₄ (s) + 6CO (g) = 2Al ₂ O ₃ (s) + SiC (s) + 9C (s) ... (1)

When Al ₄ SiC ₄ is added, the product produced through the gas phase fills the voids in the plate (refractory). As a result, the linear change of the material does not occur even if the densification progresses. For this reason, densification is maintained even at high temperatures, as compared with the case where an antioxidant such as conventional metal Al or SiC is added. Moreover, the product produced through the gas phase exerts the effect of having the property of being less likely to lead to thermal shock.
When the reaction represented by the above formula (1) proceeds, pores are formed between the particles of the raw material powder, and alumina is recondensed on the inner surface (or inside of the pores) of the pores. Will have. Identifying this structure is difficult.

Al ₄ SiC ₄ is prepared so as to be 2 to 23 mass% when the total of the prepared raw materials is 100 mass%. When Al ₄ SiC ₄ is contained in this ratio, the effect of adding Al ₄ SiC ₄ can be exhibited. If it is less than 2 mass%, the effect of densification cannot be fully exerted. Further, if it exceeds 23 mass%, the effect of densification can be exhibited, but cracks are likely to occur in the plate (refractory) during the heat treatment. The content ratio of Al ₄ SiC ₄ is more preferably 3 to 20 mass%, further preferably 5 to 15 mass%.

The particle size (average particle size) of the Al ₄ SiC ₄ powder is not limited. It is preferably a powder having an average particle size of 5 μm to 200 μm. The average particle size indicates the average particle size (D50) of the particle size distribution, and can be measured by a conventionally known method. When the average particle size is within this range, a dense plate (refractory) can be manufactured. If the average particle size is less than 5 μm, the particle size is too small and it becomes difficult to handle it. On the other hand, if the average particle size exceeds 200 μm, the average particle size becomes too large, and the pores formed by the decomposition of Al ₄ SiC ₄ become large, or the reactivity becomes low and the reaction does not proceed sufficiently. However, the effect of densification of the tissue cannot be sufficiently obtained.

Al ₄ SiC ₄ preferably has an S content of 100 ppm or less. In Al ₄ SiC ₄ , S (sulfur) contained in the manufacturing raw material (for example, carbon black which is a carbon source of Al ₄ SiC ₄ ) may remain as an unavoidable impurity. When the S content is 100 ppm or less, cracks in the plate (refractory) can be suppressed. When a large amount of S remains in Al ₄ SiC ₄ , a large amount of hydrogen sulfide gas is generated by the reactions of the following equations (2) to (3). The hydrogen sulfide gas causes cracks when the plate (refractory) is heat-treated (heat treatment of the mixed powder in the subsequent step). In the formula (2), the reaction for producing aluminum sulfide proceeds, and in the formula (3), the reaction for producing hydrogen sulfide gas by hydrolysis of aluminum sulfide proceeds.
_{^{2Al 3+ + 3S 2- → Al 2}} S 3 ··· (2)
Al ₂ S ₃ + 6H ₂ O → ₂ Al (OH) ₃ + 3H ₂ S ・ ・ ・ (3)
The carbon material serves as a carbon source for CO gas in the reaction of the above formula (1). Further, in the carbon material, voids are formed in the plate (refractory) by generating CO gas.

The carbon material is prepared so as to be 2 to 10 mass% when the total of the prepared raw materials is 100 mass%. When the carbon material is contained in this ratio, the effect of adding the carbon material can be exhibited. If it is less than 2 mass%, the effect of spalling resistance cannot be sufficiently exhibited. On the other hand, if it exceeds 10 mass%, the amount of alumina is relatively reduced, the oxidation resistance and the wear resistance are lowered, and the surface roughness of the plate (refractory) is likely to be induced. The content ratio of the carbon material is more preferably 3 to 7 mass%.

The carbon material is a material that does not form a compound with other elements and is formed only from carbon. The carbon material is preferably composed of one or more powders of scaly graphite, artificial graphite, pitch coke, and carbon black. By selecting the carbon material from these materials, CO gas can be generated in the reaction of the above formula (1). The average particle size (D50) and particle size of the carbon material powder are not limited, and are preferably equal to or less than the powder of Al ₄ SiC ₄ .

Phenolic resin is added as a binder. Phenolic resin has a water content of 1% or less. Here, 1% of the water content is a mass ratio when the mass of the phenol resin in the prepared and mixed state is 100 mass%. When the water content of the phenol resin is 1 mass% or less, the occurrence of cracks in the plate (refractory) can be suppressed. If water is contained in excess of 1 mass%, cracks will occur in the plate (refractory) in the subsequent heat treatment, especially when the heat treatment temperature is 1200 ° C. or higher. The mechanism is not clear, but I think as follows.
Due to the S contained (residual) in Al ₄ SiC ₄ , the production reaction of aluminum sulfide (Al ₂ S ₃ ) proceeds in some step in the refractory manufacturing process (the reaction of the above formula (2)). ). Then, the hydrolysis reaction of aluminum sulfide (Al ₂ S ₃ ) proceeds, and hydrogen sulfide gas (H ₂ S) is produced (the reaction of the above formula (3)). When the heat treatment is performed, the produced Al ₂ S ₃ volatilizes, and at that time, the plate (refractory) is cracked.

The phenol resin is preferably added in an amount of 1 to 5 mass% when the total amount of the prepared raw material is 100 mass%. By having this ratio, the phenol resin functions as a binder. If the amount of phenol resin is less than 1 mass%, the amount of phenol resin contained is too small, and the function as a binder cannot be sufficiently exhibited. On the other hand, if it is contained in excess of 5 mass%, the amount of water contained in the entire plate (refractory) becomes excessively large, which may cause cracks in the plate (refractory).
The phenol resin may be liquid or solid, but is preferably liquid.

The rest is one or more of alumina, alumina-zirconia, zirconia mullite, magnesia, and magnesia-spinel. These metals or compounds form the main components of the plate (refractory). The compound forming the balance is composed of powder, and its average particle size (D50) and particle size are not limited. A powder having an average particle size (particle size) sufficient for producing a conventional plate (refractory) can be used.

The prepared raw material may further be added with conventionally known additives. Examples of this additive include a silicon compound (preferably metallic Si) for producing a residual carbon material and silicon carbide, and an antioxidant (for example, metallic Al).

Then, the prepared raw materials (raw material powder) are uniformly mixed (mixing step: S2). When the phenol resin (binder) is liquid, or when a liquid dispersion medium is further used, kneading is performed. The specific method of uniformly mixing in this step is not limited. That is, they are uniformly mixed (kneaded) using a mixing device and a kneading device.

Then, the mixture (kneaded product) is molded into a predetermined shape (molding step: S3). The predetermined shape is the shape of the sliding nozzle plate. The specific method of molding the mixture in this step is not limited. That is, it is molded into a predetermined shape by using a molding method such as mold molding or compression molding.
Then, the molded product is heat-treated (heat treatment step). As the heat treatment in the heat treatment step, a drying step (S4) for drying the molded product and a firing step (S5) for firing the dried molded product are performed.

The drying step (S4) is a step of drying the molded product. The drying step is a step of heating the molded body to evaporate the water content in the molded body. The drying step (S4) is a process of heating the molded product so that water and volatile organic components can be evaporated, and the heating conditions are not limited. For example, heat treatment at 100 ° C. to 120 ° C. (in the air, under normal pressure conditions) can be mentioned.

The firing step (S5) is a step of firing the dried molded product. By firing the molded body, the reaction of the above formula (1) proceeds, and the molded body becomes a dense fired body. The firing conditions in the firing step (S5) are not limited. For example, heat treatment at 150 to 1400 ° C. (under normal pressure conditions) is preferable, and heat treatment at 200 to 1300 ° C. (normal pressure conditions) is more preferable.
The heat treatment at 150 to 1400 ° C. (under normal pressure conditions) is preferably at least one of a heat treatment at 150 ° C. to 400 ° C. and a heat treatment at 1000 to 1400 ° C. This heating condition is selected according to the conditions required for the manufactured plate.

In the heat treatment at 150 ° C. to 400 ° C., only the curing reaction of the phenol resin proceeds, and the reaction of the above formula (1) does not proceed. In this case, the reaction of the above formula (1) is allowed to proceed by further heat treatment or heat reception when the plate is actually used.

In the heat treatment at 1000 to 1400 ° C., both the curing reaction of the phenol resin and the reaction of the above formula (1) proceed. Further, in the heat treatment at 1000 to 1400 ° C., the sintering reaction between the particles of the raw material powder also proceeds, and the strength of the plate becomes higher. When the heating temperature is 1400 ° C. or higher, the residual expansion of the plate (refractory) itself becomes large, and it becomes difficult to secure the initial strength when used as a plate.
Further, the firing atmosphere may be a non-oxidizing atmosphere such as nitrogen gas or argon gas. Coke breeze may be packed in a container called a muffle and fired in it.

The fired body is impregnated with pitch (impregnation step: S6). Here, pitch is a general term for highly viscous hydrocarbons and includes tar. By impregnating the fired body with pitch, the corrosion resistance (digestion resistance) of the plate is improved. The specific method of impregnating the pitch is not limited. It can be done by a conventionally known method. In this impregnation step, the fired body is impregnated with pitch, but it may be impregnated with a material capable of exhibiting the same function. For example, a solution resin can be mentioned.
The impregnation step (S6) is an arbitrary step. That is, the plate may not be subjected to the impregnation step (S6).
In the manufacturing method of this embodiment, a plate for a sliding nozzle can be manufactured by performing each of the above steps.

The plate produced in this embodiment is formed by molding a mixture (raw material powder) of a composite carbide, a carbon material, a metal powder, an oxide and a compound, and firing the mixture. That is, the plate produced in this embodiment has a structure in which the particles of the raw material powder are fixed or sintered in a dense state by firing, and it is difficult to specify the structure.

(Effect of this form)
In the manufacturing method of this embodiment, each of the above steps (S1 to S5) is performed. In particular, a phenol resin added as a binder having a water content of 1% or less is used. By using this phenol resin, even if it is heated to a high temperature in the firing step (S5), the generation of cracks in the plate due to the hydration reaction is suppressed. That is, according to the manufacturing method of this embodiment, it is possible to manufacture a plate that is dense and suppresses the occurrence of cracks.
In the production method of this embodiment, Al ₄ SiC ₄ powder having an average particle size of 5 μm to 200 μm is used. When the average particle size is within this range, a dense plate can be manufactured.
In the production method of this embodiment, Al ₄ SiC ₄ has an S content of 100 ppm or less. According to this configuration, the generation of hydrogen sulfide gas is suppressed, and the generation of cracks in the plate due to the hydrogen sulfide gas is suppressed.
In the production method of this embodiment, the heat treatment in the firing step (S5) is a process of heating at a heating temperature of 150 to 1400 ° C. According to this configuration, a plate made of a dense fired body can be manufactured.

In the production method of this embodiment, the phenol resin is added in an amount of 1 to 5 mass% when the whole is 100 mass%. According to this configuration, the phenol resin can function as a binder, and a plate having a predetermined shape can be produced.

In the production method of this embodiment, the carbon material is made of one or more powders of scaly graphite, artificial graphite, pitch coke, and carbon black. According to this configuration, CO gas can be generated in the reaction of the above formula (1), and a plate made of a dense fired body can be produced.
In the production method of this embodiment, after the heat treatment in the firing step (S5), a pitch impregnation step (S6) for impregnating the pitch is performed. According to this configuration, a plate having improved corrosion resistance (digestion resistance) can be manufactured.

[plate]
The plate of this embodiment has 2 to 23 mass% of Al ₄ SiC ₄ and 2 to 10 mass% of carbon material, and the balance is alumina, alumina-zirconia, zirconia mullite, magnesia, magnesia-when the whole is 100 mass%. A calcined product obtained by heat-treating a mixture of one or more types of spinels and a phenol resin having a water content of 1% or less at a heating temperature of 150 to 1400 ° C.
That is, the plate of this embodiment is manufactured by the above-mentioned manufacturing method, and exhibits the above-mentioned effect.

As described above, the structure of the plate of this form cannot be unconditionally determined (that is, it is difficult to specify the structure).

Hereinafter, the present invention will be described with reference to examples.
[Examples and Comparative Examples]
As an example and a comparative example, Al ₄ SiC _{4 having} an average particle size of 20 μm to 50 μm, carbon black (carbon material) having an average particle size of 20 μm to 200 μm, sintered alumina, metal Si having a particle size of 200 mesh or less, and a particle size of 200 mesh or less. Metal Al of 200 mesh or less, fused magnesia, solution phenol resin A (water content: 0.3 to 0.8 mass%), solution phenol resin B (water content: 1.4 to 1.8 mass) %) And prepare. Al ₄ SiC ₄ had an S content of about 50 ppm. As the sintered alumina, coarse particles having an average particle size of 3 to 1 mm, medium particles having an average particle size of 1 mm to 200 μm, and fine particles having an average particle size of less than 200 μm were appropriately blended. These raw materials were in powder form except for phenol resin.
Then, the prepared raw materials are weighed at the ratios shown in Table 1, mixed uniformly, and molded into a block shape. The molded product was calcined in a non-oxidizing atmosphere at the temperatures shown in Table 1 for 24 hours.
As described above, the test pieces of Samples 1 to 13 were produced.

Samples 1 to 9 are samples in which alumina (sintered alumina) is the main component and fired (heat treated) at a high temperature. Samples 10 and 11 contain alumina (sintered alumina) as a main component and are fired (heat treated) at a low temperature. Samples 12 and 13 are samples containing magnesia (electrofused magnesia) as a main component and calcined (heat treated) at a high temperature.
Samples 1 to 4, 10 and 12 correspond to the examples of the present invention. Samples 5 to 9, 11 and 13 correspond to comparative examples. Sample 5 does not contain Al ₄ SiC ₄ . Sample 6 has a low content ratio of Al ₄ SiC ₄ . Sample 7 has an excessively high content ratio of Al ₄ SiC ₄ . Samples 5 and 8 have an excessively high water content of the phenol resin. Sample 9 has an excessively high firing temperature. Samples 11 and 13 do not contain Al ₄ SiC ₄ .

[Evaluation]
The following evaluations were performed on the test pieces of each sample. The test pieces of Samples 10 to 13 having a firing temperature of 250 ° C. were all evaluated after being reduced and fired at 1200 ° C. for 3 hours in a non-oxidizing gas atmosphere.

(appearance)
The appearance of the test pieces of Samples 1 to 13 was evaluated by 〇, Δ, and ×, and is shown in Table 1. The test piece in which no crack was confirmed was evaluated as ◯, the test piece in which some crack or deformation was confirmed was evaluated as Δ, and the test piece in which large crack was confirmed was evaluated as ×. In addition, Δ indicates a case where a small crack that can be actually used as a plate is confirmed, and × indicates a case where a large crack (deep crack) that cannot be actually used as a plate is confirmed.

(Physical properties)
Apparent porosity, bulk specific gravity, and bending strength were measured as physical property values of the test pieces of Samples 1 to 13, and are shown in Table 1.
The apparent porosity and bulk specific gravity are measured according to JIS R 2205, and the bending strength is measured according to JIS R 2213.

(Characteristic)
(Oxidation resistance test)
The test piece is placed in an electric furnace, heated to 1000 ° C. at a heating rate of about 4 ° C./min in an air atmosphere, held in the electric furnace for 3 hours (oxidation firing), and allowed to cool. The surface of the above is irradiated with SiC powder having a particle size of 20 mesh or less for 30 seconds. The weight loss value before and after irradiation of the SiC powder was obtained, and the value multiplied by the bulk specific gravity was indexed (the value of sample 5 was indexed as 100) and shown in Table 1. The smaller the value of the oxidation resistance test, the better the result (excellent in oxidation resistance).

(Corrosion resistance test)
A slag in which C (CaO) and S (SiO ₂ ) have an atomic number ratio of C / S of 1.0 is put into a high-frequency induction furnace maintained at 1580 to 1650 ° C. and melted. The test piece is immersed in the molten slag, and the test piece is rotated at 50 rpm for 300 minutes. The amount of erosion of the taken-out test piece was measured, and the amount of erosion of sample 5 was indexed as 100 and shown in Table 1. The result of the corrosion resistance test is better as the value is smaller (the amount of erosion is small and the corrosion resistance is excellent).

(Heat-resistant impact test)
The test piece is put into an electric furnace heated to 1200 ° C. and rapidly heated, and then the test piece is taken out and air is blown to quench it. The test piece after quenching was cut at a place where a crack was confirmed, and the depth of the crack was measured. The measurement results were discriminated into large, medium, and small, and are shown in Table 1. The "large" judgment result corresponds to a large number of cracks that can be seen and collapsed when touched. The "middle" of the judgment result corresponds to a crack that can be seen to some extent and does not collapse even if touched. “Small” in the judgment result corresponds to those in which cracks of about microcracks are visible to those in which cracks are not visible.

(Evaluation results)
As shown in Table 1, the test pieces of Samples 1 to 4, 10 and 12 corresponding to the examples of the present invention all have a crack-free appearance. On the other hand, in the sample 7 having an excessively high content of Al ₄ SiC _4, the sample 8 having an excessively high water content of phenol resin, and the sample 9 having an excessively high firing temperature, cracks and deformation of the test piece were confirmed. did it. In particular, in sample 8, the test piece collapsed after the heat treatment, and the evaluation test could not be performed.

As shown in Table 1, the test pieces (main component: alumina, fired at high temperature) of Samples 1 to 4 corresponding to the examples of the present invention have an apparent porosity as the content ratio of Al ₄ SiC ₄ increases. It also has physical properties that reduce the bulk specific gravity and increase the bending strength.
The test piece of sample 10 (main component: alumina, fired at low temperature) corresponding to the embodiment of the present invention has an apparent porosity and bulk as compared with sample 11 (a sample having an excessively high water content of phenol resin). It has physical properties with low specific gravity and high bending strength.
The test piece of sample 12 (main component: magnesia, fired at high temperature) corresponding to the embodiment of the present invention has an apparent porosity and bulk specific gravity as compared with sample 13 (sample not containing Al ₄ SiC ₄ ). It is small and has high bending strength.
On the other hand, in each sample corresponding to the comparative example, the physical properties of apparent porosity, bulk specific gravity, and bending strength are lower than those of each sample corresponding to the example. That is, the test piece of the example is dense and has excellent strength.

As shown in Table 1, the test pieces (main component: alumina, fired at high temperature) of Samples 1 to 4 corresponding to the examples of the present invention have oxidation resistance as the content ratio of Al ₄ SiC ₄ increases. It has high physical properties.
The test piece of sample 10 (main component: alumina, calcined at low temperature) corresponding to the example of the present invention has physical properties having higher oxidation resistance than sample 11 (sample having an excessively high water content of phenol resin). have.
The test piece of sample 12 (main component: magnesia, fired at high temperature) corresponding to the example of the present invention has physical properties with high oxidation resistance as compared with sample 13 (sample not containing Al ₄ SiC ₄ ). are doing.
On the other hand, in the sample 6 in which the content ratio of Al ₄ SiC ₄ is excessively low 6 and the sample 9 in which the firing temperature is excessively high, the index is 100 or more, and the oxidation resistance property is particularly deteriorated.

As shown in Table 1, the test pieces (main component: alumina, fired at high temperature) of Samples 1 to 4 corresponding to the examples of the present invention have higher corrosion resistance as the content ratio of Al ₄ SiC ₄ increases. Has physical properties.
The test piece of sample 10 (main component: alumina, calcined at low temperature) corresponding to the example of the present invention has physical properties with high corrosion resistance as compared with sample 11 (sample having an excessively high water content of phenol resin). are doing.
The test piece of sample 12 (main component: magnesia, fired at high temperature) corresponding to the example of the present invention has physical properties with high corrosion resistance as compared with sample 13 (sample not containing Al ₄ SiC ₄ ). There is.
On the other hand, in the sample 6 in which the content ratio of Al ₄ SiC ₄ is excessively low 6 and the sample 9 in which the firing temperature is excessively high, the index is 100 or more, and the oxidation resistance property is particularly deteriorated.

As shown in Table 1, the test pieces of Samples 1 to 4, 10 and 12 corresponding to the examples of the present invention are all excellent in thermal shock resistance. On the other hand, samples 5, 11, 13, which do not contain Al ₄ SiC ₄ , samples in which the content of Al ₄ SiC ₄ is excessively low 6, samples in which the content of Al ₄ SiC ₄ is excessively high 7, and the firing temperature are high. In the sample 9 which is excessively high, deep cracks are confirmed, and the heat impact resistance property is deteriorated.

(Summary)
From the results of each of the above tests, the test pieces of Samples 1 to 4, 10 and 12 corresponding to the examples of the present invention are dense and have high strength, and are also excellent in oxidation resistance, corrosion resistance and heat impact resistance. It has become a sample.
In particular, the sample 8 in which the water content of the phenol resin is excessively large has cracks that do not occur in the sample 2 in which the water content of the phenol resin is within a predetermined range. That is, it can be seen that by setting the water content ratio of the phenol resin within a predetermined range, the plate is dense and has high strength, and is also excellent in oxidation resistance, corrosion resistance, and heat impact resistance.

Claims (5)

1. When the whole is 100 mass%, 2 to 23 mass% of Al ₄ SiC ₄ , 2 to 10 mass% of carbon material, and the balance is one or more of alumina, alumina-zirconia, zirconia mullite, magnesia, magnesia-spinel. A method for producing a plate for a sliding nozzle, which comprises mixing a phenol resin having a water content of 1% or less and then heat-treating it at a heating temperature of 150 to 1400 ° C.
2. The method for manufacturing a plate for a sliding nozzle according to claim 1, wherein the Al ₄ SiC ₄ is a powder having an average particle size of 5 μm to 200 μm.
3. The method for manufacturing a plate for a sliding nozzle according to any one of claims 1 to 2, wherein the Al ₄ SiC ₄ has an S content of 100 ppm or less.
4. The method for manufacturing a plate for a sliding nozzle according to any one of claims 1 to 3, wherein the phenol resin is added at 1 to 5 mass% when the whole is 100 mass%.
5. The method for manufacturing a plate for a sliding nozzle according to any one of claims 1 to 4, wherein the carbon material is made of one or more powders of scaly graphite, artificial graphite, pitch coke, and carbon black.

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